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United States Patent |
6,029,946
|
Doyle
|
February 29, 2000
|
Needleless valve
Abstract
A needless valve is described which avoids the suctioning problems of the
prior needleless devices upon deactivation and which preferably provides a
positive self-purging effect. The valve is self-purging at the end of an
administration cycle, avoiding clogging of attached catheters or other
devices, and ensures that substantially all of liquid received into the
valve is delivered to the receiver. The valve is also extremely simple in
design and easy to construct and assemble, since it consists of only three
pieces. The valve has a base with a connector for fluid communication
attachment to tubing or other device, a solid elongated fluid channeling
rod, and an internal fluid flow conduit; a flexible hollow expandable and
contractible plug fitting over and moveable along the rod; and a tubular
housing fitting over the plug and attached to the base. When the valve is
activated by insertion of a nozzle of a fluid source, the rod and plug
wall cooperate so that as the plug retracts along the rod, it is stretched
and its interior expanded. Upon deactivation, the plug contracts, the
interior volume decreases, and the resiling plug wall forces residual
fliud within the valve to be expelled through the outlet, purging the
residual fluid from the valve. No negative pressure is formed, so no
suctioning of blood or other fluid from a patient or receiver occurs.
Inventors:
|
Doyle; Mark Christopher (San Diego, CA)
|
Assignee:
|
Tiva Medical Inc. (Carlsbad, CA)
|
Appl. No.:
|
929919 |
Filed:
|
September 15, 1997 |
Current U.S. Class: |
251/149.1; 604/249; 604/256 |
Intern'l Class: |
A61M 005/00 |
Field of Search: |
251/149.1,149.6,118
604/249,256
|
References Cited
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| |
Foreign Patent Documents |
9311828 | Jun., 1993 | WO.
| |
Primary Examiner: Lee; Kevin
Attorney, Agent or Firm: Brown, Martin, Haller & McClain
Claims
I claim:
1. A needleless valve comprising a tubular housing having a fluid inlet end
and a fluid outlet end, a solid rod disposed between said fluid inlet end
and said fluid outlet end within said housing and having expander means
extending therefrom, and a hollow flexible plug within said housing
overlying said rod and moveable therealong away from said fluid inlet end
in response to insertion of a fluid supply nozzle into said inlet end and
toward said fluid inlet end in response to withdrawal of said fluid supply
nozzle from said inlet end, said hollow plug cooperating with said
expander means of said rod to increase the volume of the interior of said
plug during movement away from said fluid inlet end and cooperating with
said expander means of said rod to decrease the volume of said plug
interior during movement toward said fluid inlet end, whereby a fluid flow
path between said inlet and outlet ends is alternately opened and closed
and upon closing of said flow path residual fluid therein is expelled from
said valve through said outlet end.
2. A needleless valve as in claim 1 further comprising said rod being
elongated coaxially of said valve and said expander means comprising a
plurality of longitudinal ribs extending outwardly therefrom, said ribs
cooperating with said plug in said increase in said interior volume and in
said decrease in said interior volume.
3. A needleless valve as in claim 2 wherein the distance a rib extends
outwardly from said core varies over the length of said rib.
4. A needleless valve as in claim 3 wherein the distances of outward extent
of said rib varies continuously over the length of said rib.
5. A needleless valve as in claim 3 wherein the distances of outward extent
of said rib varies discontinuously over the length of said rib.
6. A needleless valve as in claim 2 further comprising said ribs
terminating adjacent said outlet end in a hollow annular member encircling
said rod.
7. A needleless valve having a distal end and a proximal end, and
comprising:
a base disposed at said proximal end and comprising a connector for fluid
communication attachment to a fluid flow tube, a solid elongated fluid
channeling rod extending from a proximal end joined to said base to a
distal end, and a fluid flow conduit formed in said base and extending
through said connector into said proximal end of said rod and disposed for
said fluid communication with said tube;
a flexible plug having a wall forming a hollow interior bounded by an
inward facing surface; said plug fitting over said rod, being sealingly
attached to said base and being moveable along said rod between a first
activated position and a second deactivated position; in said first
activated position said rod maintaining said plug in a form with said
interior having a first larger volume, with said plug withdrawn from said
distal end of said rod, and creating a fluid flow path through said
interior and along said rod; and in said second deactivated position said
plug being in a form with said interior having a second smaller volume
with said distal end of said rod covered by said plug and said fluid flow
path being blocked by said wall of said plug; and
a tubular housing fitting over said plug and extending from said distal end
of said valve to said base, at said distal end said housing having an
elongated receiver for releasable fluid communication reception of a
nozzle of a fluid source, said receiver configured to guide movement of
said nozzle along said receiver into contact with said plug, said plug
moving between said first and said second positions in response to
movement of and contact from said nozzle;
such that movement of said plug from said first position to said second
position in response to insertion of said nozzle into said receiver
causing said rod and said plug to cooperate to expand said plug and
increase said interior volume and open said valve to fluid flow between
said source and said tube, and subsequent movement of said plug from said
second position to said first position in response to withdrawal of said
nozzle from said receiver causing said plug to resile and said interior
volume to decrease, closing said valve to said fluid flow, displacing
residual fluid within said valve and causing said residual fluid to flow
from the proximal end of said valve into said tube.
8. A needleless valve as in claim 7 further comprising said rod being
elongated coaxially of said valve and having a plurality of longitudinal
ribs extending outwardly therefrom, said ribs cooperating with said plug
in said increase in said interior volume and in said decrease in said
interior volume.
9. A needleless valve as in claim 8 wherein the distance a rib extends
outwardly from said core varies over the length of said rib.
10. A needleless valve as in claim 9 wherein the distances of outward
extent of said rib varies continuously over the length of said rib.
11. A needleless valve as in claim 9 wherein the distances of outward
extent of said rib varies discontinuously over the length of said rib.
12. A needleless valve as in claim 8 further comprising said ribs
terminating adjacent said outlet end in a hollow annular member encircling
said rod.
13. A needleless valve as in claim 7 wherein said cooperation between said
rod and said plug as said plug interior decreases in volume creates a
transient positive pressure against residual fluid enhancing said
expulsion of said fluid from said valve into said tube.
14. A needleless valve as in claim 7 wherein said flexible plug is formed
of a resilient material.
15. A needleless valve as in claim 7 further comprising an interior surface
of said housing adjacent said proximal end forming a chamber surrounding
said rod and a portion of said plug, said chamber being filled with gas,
such that said expansion of said plug into said chamber causes compression
of said gas, said compressed gas thereafter acting to enhance resiling of
said plug and decrease of said interior volume.
16. A needleless valve as in claim 7 wherein said plug comprises an
expanded proximal section which upon activation enhances the degree of
expansion of said interior volume.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention herein relates to valves and connectors, such as those use in
medical liquid flow applications such as intravenous (IV) administration
of medications. More particularly it relates to needleless valves for such
applications.
2. Description of the Prior Art
There are many instances, particularly in the medical field, where
quantities of liquid must be moved from a source of the liquid to a liquid
conduit system under restricted and usually sterile conditions. A
principal example is the administration of medication or other liquids to
a patient intravenously. When the intravenous administration is to be
conducted at periodic intervals over a extended period of time, the
conventional practice is to insert a catheter into the patient's vein,
usually through the patient's forearm, and leave the catheter in place
with a portion extending out of the patient's arm and terminating in a
valve (receiver) for periodic connection to the liquid source as required.
The presence of the valve avoids the necessity of using direct injection
of the patient each time the medication is to be administered, which would
be both painful to the patient and also increase the risk of infection
each time the skin was penetrated.
For many years, receivers of valves were constructed with a resealable
membrane, such as a rubber or other elastomeric plug, stretched across the
inlet end of the device, closing off the IV fluid conduit. When it was
time to administer medication or other fluid, the physician or nurse would
use a conventional hypodermic syringe with a sterile hypodermic needle
which would penetrate the rubber plug and allow sterile injection of the
fluid in the syringe directly into the liquid conduit or cannula. Upon
withdrawal of the hypodermic needle, the elastic rubber plug would resile
and seal itself, maintaining the sterile condition of the interior of the
system.
Such practice, however, has numerous disadvantages. Repeated piercing of
the plug with the hypodermic needles eventually damages the plug
sufficiently that it cannot maintain the appropriate sterile seal.
Further, since the valve/receiver devices are normally quite small, the
plug is even smaller, often less than 1/4 inch (6 mm) in diameter.
Therefore the person administering the medication had to take care in
manipulating the syringe so that the hypodermic needle would pierce the
rubber plug and not hit the other portions of the receiver, the patient's
arm, or even the hands or arms of the person himself or herself. To take
the appropriate amount of care, of course, required some period of time,
thus reducing the number of patients a physician or nurse could serve in a
given time period. In addition, it was not uncommon for hypodermic needles
to break off in the plug during or before administration of the liquid,
thus usually becoming lodged in the rubber plug and requiring the
administrator to take time to remove the broken needle. Further, such
breakage also commonly caused the loss of all or a portion of the
medication or other liquid in the syringe and, of course, not properly
administered to the patient.
Such problems were particularly common in situations where the medical
personnel were required to act very rapidly, such as in emergency room and
emergency medical administration settings.
The accidental piercing of the skin of the doctor or nurse raised critical
problems. If such occurred before administration of the medication to the
patient, the medication, or at least a portion of it, was injected into
the nurse or doctor, which not only deprived the patient of the
medication, but in fact might be quite harmful to the physician or nurse.
If the accident occurred after administration of the fluid to the patient,
the hypodermic needle could easily be contaminated by the patient's blood
or other bodily fluid, thus being capable of transmitting the patient's
disease to the physician or nurse. While this was a severe problem at any
time, it became a truly critical problem as various highly infectious or
virulent diseases became more prevalent in the population. The added
presence of infectious diseases with extremely high rates of mortality
among patients, such as AIDS, gave priority to development of devices
which would eliminate the need for use of hypodermic needles.
In more recent years, "needleless" connectors and receptors have been
developed and widely marketed. In systems using this type of device, the
fluid dispenser (usually a syringe) is fitted with a blunt nozzle rather
than a hypodermic needle. The blunt nozzle is designed to be received into
a corresponding receiver attached to the IV line or other fluid conduit.
Within the receiver is normally a hollow tubular cannula, which is a fixed
member forming the extended end of the fluid conduit extending into the
patient's veins. Sterility of the receivers is important so that transfer
of the liquid from the syringe to the cannula and IV fluid conduit can be
conducted under sterile conditions.
While the "needleless" concept has been well known and is quite simple,
implementation of the concept in practice has been quite difficult.
Needleless connectors have, for the most part, been designed with a hollow
flexible plug which fits over the cannula and which has a self-sealing
slit or similar closeable opening in its exterior end. The interior end of
the plug is anchored adjacent to the downstream end of the cannula (i.e.
the end leading into the IV system and the patient's arm). Since the
cannula is made as a rigid elongated tube, as the nozzle of the fluid
dispensing device is pushed into the receiver, it contacts that exterior
end of the rubber plug and forces that end inwardly against the distal end
of the cannula. The distal end of the cannula contacts the slit at the end
of the plug and forces the slit open, so that the plug then becomes a
sleeve as it is pushed inwardly along the outer surface of the cannula.
Eventually, the distal end of the cannula, now being exposed, contacts the
interior fluid transfer tube of the dispensing device as the nozzle of the
dispensing device moves further into the receiver. When this connection is
made, the fluid can be transferred from the syringe directly into the
cannula through which it flows onto the IV system in the patient's body.
Such opening of the device is commonly referred to as "activation" of the
"valve."
Once the fluid is fully transferred, the nozzle of the dispensing device is
withdrawn outwardly through the receiver, causing the flexible plug to
resile and extend distally along the cannula until it passes the cannula
end and returns to its "deactivated" position enclosing the end of the
cannula with the slit again sealed. Examples of devices of this type are
shown in U.S. Pat. Nos. 5,065,783 (Ogle) and 5,549,577 (Siegel et al.) and
in published PCT application no. WO 93/11828 (Lopez).
While such devices have worked well for the most part, they have been found
to have some serious deficiencies. One of the most important is the fact
that upon deactivation and withdrawal of the nozzle of the syringe or
other fluid dispensing device, the compressed plug resiles back to its
original position, thus increasing its internal volume back to its
deactivated volume, thus creating a partial vacuum in the cannula and
attached catheter. This produces a suctioning effect which often causes
the patient's venous blood to be drawn into the catheter where it remains
and can clot, thus preventing flow through the catheter. When it comes
time to administer the next fluid dose, the plugged catheter prevents
administration of the fluid. Remedying of the problem requires that the
catheter be cleaned or replaced. This, of course, is a major problem in
emergency situations, whether in an emergency room or when a patient on IV
suffers some sort of relapse or seizure or other critical condition and
medication must be administered through the IV without delay. Even in the
absence of an emergency, however, withdrawal of the device for cleaning of
the catheter requires that the IV subsequently be reinserted into the
patient. In ordinary situations this at least requires the time of a nurse
and is a discomfort for the patient. In many cases, however, reinsertion
is a problem that requires a doctor's intervention, as for instance where
an new acceptable insertion site is difficult to find or the patient does
not tolerate needle insertions well. Thus reinsertion presents a
significant cost event for the medical team and subsequently for the
patient.
Other forms of connectors in needleless couplings have been described.
These may have components within the coupling intended to hold the fluid
flow conduit open against the tendency of flexible sleeves attached to one
or the other end of a coupled tubing to compress and close the fluid flow
path. A typical example is shown in U.S. Pat. No. 4,457,749 (Bellotti et
al.) in which a "spike" having a cruciform cross section is used to hold
open a fluid path within the coupling as the two portions of the tubing
are joined together.
SUMMARY OF THE INVENTION
I have now invented a needless valve which avoids the suctioning problems
of the prior needleless devices and which, in fact, can be structured to
provide a positive self-purging effect upon deactivation. This device
retains all of the favorable aspects of the needleless valve system for
activation and administering the medication to the patient, but avoids all
of the detrimental effects of the prior art devices that occur during
deactivation. The present device is virtually impossible to clog, is
self-purging at the end of an administration cycle, and helps ensure that
substantially all of the medication dispensed from the syringe is
administered into the patient. The device is also extremely simple in
design and easy to construct and assemble, since it consists of only three
pieces. The device may be made in a variety of different configurations,
all of which provide the same self-purging action and clear flow path for
the administered liquid.
The device of this invention is configured so that a core rod forces the
plug to expand during activation in a manner not possible with the prior
art devices, which causes the interior volume of the plug to increase
substantially from its rest (deactivated) volume and opens a flow path
through the valve for the administered fluid. Upon deactivation, the plug
resiles and its interior volume returns to rest volume, closing the fluid
flow path and displacing residual fluid within the valve, so that the
residual fluid is expelled from the valve through its outlet into the
downstream conduit or unit, purging the valve and promoting use of all of
the administered fluid. In addition, such volume decrease prevents
occurrence of any partial vacuum in the valve, and in fact usually creates
a transient overpressure, which also assists in purging the valve of
residual fluid. The structure thus maintains either a positive or neutral
(i.e., non-negative) pressure at all times, preventing any suctioning of
blood from a patient into an attached catheter, thus avoiding clogging of
the catheter by formation of clots in blood drawn into it.
In a broad embodiment, the invention involves a needleless valve comprising
a tubular housing having a fluid inlet end and a fluid outlet end, a solid
rod within the housing, and a hollow flexible plug within the housing and
moveable along the rod, the hollow plug in response to insertion of a
fluid supply nozzle into the inlet end moving in one direction along and
cooperating with the rod to increase the volume of the interior of the
plug and open a fluid flow path between the inlet and outlet ends, and in
response to withdrawal of the fluid supply nozzle from the inlet end
moving in an opposite direction along and cooperating with the rod to
decrease the volume of the plug interior, close the fluid flow path
between the inlet and outlet ends and cause residual fluid in the flow
path to be expelled from the valve through the outlet end.
In another broad embodiments, the invention involves a needleless valve
having a distal end and a proximal end, and comprising a base disposed at
the proximal end and comprising a connector for fluid communication
attachment to a fluid flow tube, a solid elongated fluid channeling rod
extending from a proximal end joined to the base to a distal end, and a
fluid flow conduit formed in the base and extending through the connector
into the proximal end the rod and disposed for the fluid communication
with the tube; a flexible plug having a wall forming a hollow interior
bounded by an inward facing surface; the plug fitting over the rod, being
sealingly attached to the base and being moveable along the rod between a
first activated position and a second deactivated position; in the first
activated position the rod maintaining the plug in a form with the
interior having a first larger volume, with the plug withdrawn from the
distal end of the rod, and creating a fluid flow path through the interior
and along the rod; and in the second deactivated position the plug being
in a form with the interior having a second smaller volume with the distal
end of the rod covered by the plug and the fluid flow path being blocked
by the wall of the plug; and a tubular housing fitting over the plug and
extending from the distal end of the device to the base, at the distal end
the housing having an elongated receiver for releasable fluid
communication reception of a nozzle of a fluid source, the receiver
configured to guide movement of the nozzle along the receiver into contact
with the plug, the plug moving between the first and the second positions
in response to movement of and contact from the nozzle; such that movement
of the plug from the first position to the second position in response to
insertion of the nozzle into the receiver causing the rod and the plug to
cooperate to expand the plug and increase the interior volume and open the
valve to fluid flow between the source and the tube, and subsequent
movement of the plug from the second position to the first position in
response to withdrawal of the nozzle from the receiver causing the plug to
resile and the interior volume to decrease, closing the valve to the fluid
flow, displacing residual fluid within the valve and causing the residual
fluid to flow from the proximal end of the valve into the tube.
In another embodiment the invention also comprises a rod for a needleless
valve comprising a solid elongated core having a plurality of coaxial ribs
extending outwardly therefrom.
Ribs made be made with a uniform width so that their extended edges are
straight, with continuously varying widths so that their edged form
straight or curved smooth tapers, or have discontinuously varying widths,
so that their edges form one or more steps over the length of each rib. In
one embodiment, the ribs terminate at the distal end of the rod in a
hollow annular member encircling the rod.
Additional features of the invention as well as descriptions of the various
forms of the components will be set forth below.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the device of this invention, with the
individual components thereof shown in separated relationship;
FIG. 2 is an enlarged sectional view taken on Line 2--2 of FIG. 1;
FIG. 3 is an enlarged sectional view taken on Line 3--3 of FIG. 1;
FIG. 4 is an enlarged sectional view taken on Line 4--4 of FIG. 1;
FIG. 5 is a sectional view taken on Line 5--5 of FIG. 4;
FIG. 6 is a sectional view taken on Line 6--6 of FIG. 3;
FIG. 7 is a sectional view with the components of FIGS. 2, 3 and 4 shown in
assembled relationship;
FIG. 8 is a view similar to FIG. 7, with the valve opened by attachment of
a typical Luer-Lok connector;
FIG. 9 is a sectional view taken on Line 9--9 of FIG. 7;
FIG. 10 is a sectional view taken on Line 10--10 of FIG. 8;
FIG. 11 is a sectional view taken on Line 11--11 of FIG. 8;
FIG. 12 is a perspective view of an alternative embodiment of flexible
valve component;
FIG. 13 is a sectional view similar to FIG. 7 showing the alternative valve
component in closed position;
FIG. 14 is a sectional view taken on Line 14--14 of FIG. 13;
FIG. 15 is a view similar to FIG. 13 showing the valve component opened by
insertion of a Luer connector; and
FIG. 16 is a sectional view taken on Line 16--16 of FIG. 15.
FIG. 17 is a perspective view illustrating another embodiment of a central
rod of the present invention.
DETAILED DESCRIPTION AND PREFERRED EMBODIMENTS
The device is best understood by reference to the drawings. For the
purposes of description herein, the following conventions of direction
will be maintained. The terms "upstream" and "downstream" will be with
respect to the normal direction of fluid flow during administration of
medication or other liquid through the valve of the present invention to a
patient or other receiver. This is indicated in FIG. 8 by the flow arrows
50 (upstream) and 52 (downstream). Similarly, the terms "distal" and
"proximal" will be used with respect to the patient or other receiver,
such that the upstream end of the device is also sometimes referred to as
the distal end, while the downstream end is also sometimes referred to as
the proximal end.
One embodiment of the overall device 2 is shown in FIG. 1, separated into
three components: a base 4, plug 6 and housing 8. The principal features
of each of the parts may also be seen in FIG. 1. The base 4 consists of a
connector 10 which connects the device with the fluid flow tubing or
conduit 48, usually through a separate connector 94, as illustrated in
FIG. 8; a radial flange 12, which serves as a seat for attachment of the
plug 6; and an elongated rod 14 which, as will be described below,
cooperates with the plug 6 to provide the unique and desirable operating
features of the present invention.
The plug 6 has a seating gasket 16, a compressible mid-section 18 which
usually folds into a configuration similar to a bellows, and, at the
distal end 20, has a closeable slit or similar opening 22. The housing 8
has a wide diameter expansion portion 24, a coupling ring 26 which, during
assembly, is bonded to the flange 12 to retain the device as a single unit
and a receiving portion 28, the distal end 30 of which can be configured
as shown with threads 32 to join with corresponding threads of a liquid
dispenser to couple the two together.
FIGS. 2, 3 and 4 show respectively the housing 8, plug 6 and base 4 in
cross-section to facilitate understanding of their operations and
functions. Considering first FIG. 4, the base 4 is formed of the
aforementioned coupler 10, flange 12 and rod 14. As will be seen from FIG.
4, the coupler 10 is has an annular form with its inner wall 34 formed
into threads or ribs 36 to allow it to be attached to a corresponding
threaded end of coupler such as 94 as will be described below. Centrally
disposed within the annular shaped coupler 10 is a hollow tapered cylinder
40 which has fluid flow channel 38 extending through it. Cylinder 40 is an
extension of the flange 12 and rod 14 so that it will be desirable for the
entire base unit to be molded as a single piece of rigid material,
commonly plastic but also possibly of metal. The fluid flow conduit 38
continues as conduit 42 through the center of flange 12 and terminates as
a conduit 46 within the proximal end 44 of rod 14. Fluid flowing
downstream along rod 14 from the liquid dispenser 116 during activation of
the device 2 thus enters the fluid conduit 46 through the openings 146,
flows through aperture conduit 42 through flange 12, and on through the
channel 38 into coupler 94 and eventually into tubing 48 as shown in FIG.
8. The extension of cylinder 40 beyond the proximal end of the base 10
facilitates insertion into the coupler 94 or (in the absence of such a
coupler) directly into, for example, tubing 48. Tubing 48 may be
substituted for by other devices to which the valve is to be attached,
such as direct coupling to a storage, test or reaction vessel or to a
measuring instrument.
A preferred embodiment of a plug 6 is shown in FIG. 3. The plug 6 is made
out of a flexible material, usually a rubber or a polymeric elastomer. In
the embodiment shown the plug has a flange 16 which has a flat base 54 to
allow it to seat against the corresponding flat distal face 56 of the
flange 12 on the base 10, as shown in FIGS. 7 and 8. The most proximal
section 18 may be scored with groves 58 on the interior and exterior to
permit bellowing or other folding of the section as the plug is compressed
and moved posteriorly during activation, as best illustrated in FIG. 8.
(Another embodiment of the plug 6 will be discussed below, which has a
different form of section 18.) In other embodiments the flange 12 may be
eliminated and other means, such as a gripping or adhesive-coated surface
(not shown) provided to which the proximal end of plug 6 is secured.
In the preferred embodiment shown in the drawings, the plug 6 also has an
intermediate section 60 which can be expanded, but which does not normally
flex, fold or compress as extensively as section 18. Both the expansion
and compression of section 18 and the expansion of section 60 contribute
to the self-purging action of the device 2 as will be described below. The
distal portion 62 of the plug 6 extends outwardly just past the tip 64 of
rod 14 and normally has a somewhat thicker wall than do sections 18 and 60
to accommodate the opening and subsequent closing of slit 22 in the distal
end 20 and to resist buckling of the end 20 when the unit is deactivated.
Preferably the slit 22 will be terminated on the interior side of the plug
10 by a "duck bill" flange 66 which assists in causing the slit 22 to
resist leakage when internal pressure is present during deactivation.
The housing 8 is a simple rigid shell of plastic or metal, which is
intended to fit over the plug 6 and attach to flange 12, thus locking
gasket 16 in position, as best shown in FIGS. 7 and 8. The inner portion
of coupling ring 26 of housing 8 is configured with a generally
semi-circular channel 70 incorporated within it, both of which are
configured to accommodate the corresponding base 72 and lip 74 of gasket
16. When the connecting ring 26 is seated against the flange 12 of base 4,
preferably aligned by groove 76 into which rib 78 fits, and the two are
sealed together as by a conventional adhesive or by heat, ultrasonic or RF
welding, the flange 16 of the plug 6 is firmly held against the flange 12
so that the plug cannot be displaced, and also to provide a firm base for
subsequent return or resiling of the plug 6 upon deactivation.
The interior of section 24 of the housing 8 is configured to have a
substantially greater diameter than the deactivated rest diameter of
section 18 of the plug 6, as indicated in FIG. 7, creating an annular
space 80 into which the portion 18 can expand as it is compressed to form
the generally bellowed configuration shown in FIG. 8.
The rod 14 can have a number of different configurations, all of which are
intended to cause the plug 6 to expand outwardly during activation, thus
creating the expansion of the elastic plug and increase of its interior
volume, so that the plug 6 upon deactivation will return or resile
inwardly, decreasing its interior volume and thereby purging fluid from
the fluid flow space 82 along the rod 14. The rod 14 can be generally
described as having a solid core 84 which terminates in a blunt or rounded
tip 64 and which has extending radially outwardly therefrom a plurality of
ribs 86 (and perhaps also 86'). The ribs 86 may have various
configurations which will cause the plug to expand and which will prevent
prolapsing of the plug during activation. For instance, in various
embodiments, an elongated rib may be uniform width over most of its length
(with preferably a transition curve or slope at its distal end, to
facilitate movement of the end 20 of plug 6 along the rod and rib), or it
may have a continuously varying width, so that it has a straight or curved
tapered profile, or it may have widths that vary discontinuously along its
length, so that it has a stepped profile. It is preferred that for ribs in
which the widths vary, either continuously or discontinuously, the widths
increase from distal to proximal ends, so that no recess or shoulder is
formed upon which a portion of the interior of the plug wall could become
snagged, preventing or impeding return or resiling of the plug upon
deactivation. In yet another alternative, shown in FIG. 17, the proximal
ends of the ribs 86 may terminate in a hollow annular member 68 which
serves to maintain the maximum expansion of the plug 6 during activation.
Conveniently this annular member 68 will be circular, but polygonal shapes
are also usable, although polygons of less than six, and probably less
than eight, sides should probably be avoided, since they may be unduly
angular and tend to impede resiling of the plug upon deactivation.
There may be any convenient number of ribs and they may be disposed at any
desired orientation to each other around the circumference of the rod 14.
However, normally there will need to be at least three ribs 86, preferably
equally spaced at 120.degree. from each other, in order to ensure that the
elastic plug 6 is stretched to form a space 82 of appropriate volume.
Typically there will be four ribs 86 in a cruciform shape as indicated in
FIGS. 9 and 10; although a larger number of ribs, such as eight as shown
in FIG. 5, may also be used. It is also possible, and usually preferred,
to have different numbers and lengths of ribs on the same rod 14, as
illustrated in FIGS. 1 and 5, where the added ribs 86' are interspersed
between the principal cruciform ribs 86 but are foreshortened in axial
length and extend distally only as far as the length of the widest section
of each rib 86. The added ribs help support the extended plug wall and
prevent prolapse of unsupported portions of the wall and expansion
increases and the wall thickness is thinned by stretching. Given the small
size of the device and the desire to maximize the flow channels, it is
considered that eight to ten ribs are probably the maximum practical
number, with four, six or eight ribs being preferred, and other numbers
(both between three and ten and greater than ten) being possible. Use of
an even number of ribs as shown in the illustrations is preferred since it
is easier to mold symmetrical ribs equally spaced than to mold an
asymmetric configuration as would be present with and odd number of ribs.
Further, the number of width steps may be two or three as shown or may be
more, although again the small size of the device acts as a practical
limitation on the number of width steps of the ribs 86 which are either
feasible or desirable.
An alternative embodiment of the plug 6 is shown as 6' in FIGS. 12-16. In
this embodiment, the plug 6' is configured with an expanded downstream
section 18' which substantially replaces sections 18 and 60 in the
configuration described above. The section 18' may be somewhat bulbous or
it may approximately conform to the shape of the rod 14 (shown in these
Figures with an alternative form of the ribs designated as 86"), with the
plug 6' having conforming hollow ribs 88. The operation of this
alternative plug 6' is illustrated in FIGS. 13 and 15. In the deactivated
state, shown in FIG. 13, the plug is essentially in the shape shown in
FIGS. 12 and 14. Upon activation by the nozzle 90 of a liquid dispenser,
the bulbous section 18' with ribs 88 expands outwardly (as shown in FIGS.
15 and 16) into space 80 and leaves an enlarged open space 92 between the
rod 14 and the interior wall surface of the plug 6'. Upon deactivation the
plug 6' resiles or is caused to return to the configuration shown in FIG.
13.
It will be evident to those skilled in the art that there are, of course,
other configurations of the plug 6 other than that of 6', which will
provide equivalent expansion of the plug and increase of its interior
volume during activation, and guide the subsequent resiling of the plug
and decrease of its interior volume to produce the unique self-purging
effect present in the claimed device. It is intended that all such
configurations are to be considered within the scope of this invention as
defined in the appended claims.
The operation of the invention can best be understood by reference to FIGS.
8, 10 and 11. In a typical application, device 2 is attached to a
Luer-Lok.TM. coupler 94. Coupler 94 is formed with a hollow cylindrical
connector 96 which extends into the recess 98 inside coupler 10 and which
is secured therein by threads 100 cooperating with ribs or threads 36 on
the interior of the coupler 10. In the embodiment shown, cylinder 40 has a
tapered outer surface 102 which causes a wedging action with the interior
of connector 96 as indicated at 104, such that as the connector 94 is
turned and threaded into the recess 98 the cylinder 40 and connector 96
are tightly wedged together sealing against any loss of fluid.
Alternatively both cylinder 40 and connector 96 can be straight with
parallel surfaces, and they can be secured together by an adhesive, such
as a solvent adhesive, as shown at 97 in FIG. 15.
Preferably the design of the tapered cylinder 40 and connector 96 are such
that the end 106 of cylinder 40 and the opposing surface 108 on the
interior of connector 96 are closely adjacent or abutting such that the
space 110 between them is minimized.
Connection of the device of this invention to tubing 48 or any other device
may be configured to be releasable or permanent, as desired. In the
embodiment shown, the connector has at its opposite end a nipple 112 to
which the conventional tubing 48 is attached. The tubing is normally
stretched slightly as indicated at 114 so that the tubing 48 is retained
on the nipple 112 by the combination of the elastic resiliency of the
tubing and the interference fit between the inner surface of the tubing 48
and the outer surface of the nipple 112. If there is concern that the
tubing 48 may separate from the nipple 112, a conventional external clamp
(not shown) may be placed around the circumference of the tubing 48 where
it overlaps the nipple 112 and tightened to ensure good connection between
the tubing and the nipple. Alternatively various adhesives or solvents may
be used to secure the tubing and nipple together. The solvents or
adhesives must be selected such that they do not intrude into the fluid
flow path of the device or migrate to cause unwanted adhesion elsewhere in
the device.
Activation and deactivation of the valve 2 will be best understood by
comparison of FIG. 7 and 8. The device in its deactivated configuration is
shown in FIG. 7, with the plug 6 in its "rest" or fully resiled
orientation. (For purposes of comparison, it will be understood that
connector 94 and tubing 49 of FIG. 8 should be imagined also to be present
in FIG. 7.) Activation comprises joining of the needleless valve 2 to a
liquid supply source such as a syringe or other reservoir device,
partially shown at 116 in FIG. 8. Connection is usually through a coupler
118 which is similar in configuration to the coupler 10 of the valve.
Coupler 118 consists of an outer cylindrical wall 120 which has on its
inner side ribs or threads 122. Aligned with the center axis of coupler
118 is nozzle 90 which extends outwardly from the end 124 of coupler 118
and which is tapered to fit into the receiving portion 126 of section 28
of the housing 8. The interior of nozzle 90 is an open fluid flow channel
128 which is in fluid communication with the interior 130 of liquid
reservoir 116. The reservoir 116 is here illustrated as a conventional
syringe device, with a movable piston 132 housed within a cylinder 130.
The piston 132 is manipulated by the physician or nurse as indicated by
the arrow 50 to force the liquid forward. Such use and operation of the
fluid dispensing device 116 are conventional and need not be described
further. Similarly, such devices may take many different forms, all of
which are equally applicable to the present invention.
As the coupler 118 is moved forward (as indicated by the arrow 134) by
interaction of the threads 32 and 112, the tapered nozzle 90 interacts
with the inner surface 136 of the receiver section 126 of the housing to
create a wedging action similar to that described above between the
connectors 94 and 10, thus forming a mechanically tight connection.
Simultaneously the front end 138 of coupler 118 comes into contact with
distal end surface 20 of plug 6 and forces the plug 6 to compress in the
downstream or proximal direction, thus causing the slit 22 to contact the
tip 64 of rod 14 and be forced open as it passes over and around the tip
64, as best illustrated in FIG. 11. The compressive movement of the rest
of the plug 6 caused by the forward motion of the nozzle 90 causes the
other portions of the plug 6 to move along corresponding sections of the
rod 14 and ribs 86 (and 86', if present), thus forcing the wall of the
plug 6 to be stretched and expanded outwardly, substantially increasing
the interior volume of the plug 6 and creating the space 82 through which
the fluid can flow along the surfaces of rod 14 and ribs 86. With the plug
6 thus retracted, the liquid can flow freely from the liquid reservoir or
supply device 116 through the nozzle 90 and the now-opened slit 22, along
and adjacent to the outer surfaces of the rod 14 and ribs 86 (through the
elongated V-shaped spaces 82 formed by adjacent ribs 86, the rod 14, and
the inner surface of the plug 6, and on through the openings 146 and into
the conduits 46, 42 and 38, on through the channel 140 in the nipple 112
and into the interior 142 of tubing 48, and subsequently to the patient or
other receiver.
Because the liquid source 116 and the valve 2 are securely locked together
by the interaction of threads 32 and 112 and the wedging action of the
receiver 126 and nozzle 90, this activated configuration is stable and can
be maintained for as long as the physician, nurse or other user wishes to
continue dispensing the liquid. It can also, of course, be maintained for
an extended period of time without human supervision or control, where the
reservoir or liquid supply device 116 is mechanically or electrically
operated and provides a continuous or intermittent flow of fluid through
the valve 2 to the patient or receiver.
In prior art devices, the flexible plug merely slid along the outside of
the tubular cannula. Since the cannula had a uniform diameter, the plug
remained strongly compressed over substantially all of its length, being
stretched or expanded only at the distal tip, and then only by the minimal
amount necessary to open the end slit and allow the end of the hollow
cannula to protrude into the nozzle of the fluid dispensing device. As the
nozzle of the dispensing device was subsequently withdrawn and the plug
allowed to resile back in the distal direction along the outer surface of
the cannula and closed over the open end of the cannula, a partial vacuum
was created in the cannula. This in turn commonly resulted in liquid being
withdrawn from the patient or receiver and pulled by suction back into the
catheter to which the cannula of the prior art device was connected. Where
the receiver was a human patient, the fluid drawn back into the cannula
would usually consist in whole or in part of venous blood. The blood thus
retained in the cannula would thereafter often congeal and coagulate,
causing blockage of the hollow interior cannula and making subsequent
administration of fluid difficult or impossible until the valve and
cannula were either replaced or cleaned.
FIG. 8 illustrates the improvement of the present invention in which such
creation of partial vacuum is entirely avoided and the self-purging
property of the device is illustrated. The plug, by being stretched to
increase the interior volume during activation, resiles and decreases that
volume during deactivation, so that the contraction of the plug wall into
the space 82 (essentially eliminating space 82) displaces substantially
all residual fluid remaining within the valve upon deactivation, and
forces it to be expelled through the exit conduits. In addition, the
resiling of the plug wall often creates a transient overpressure which
also assists in expulsion of the residual fluid. Since the plug ultimately
resiles back to its rest configuration the overpressure decreases to
neutral pressure. Because the center member of this device is solid rod 14
rather than an open cannula, the end 20 of resiling plug 6 passes over
distal end 64 of rod 14 and slit 22 closes before the decrease in interior
volume, and therefore purging action of the resiling plug, is completed.
Consequently, unlike in the prior art valves, no negative pressure is
formed by the movement of end 20 and the closing of slit 22.
The self-purging and pressure-creating operation of the device is evident
from FIG. 8. As the nozzle 90 is withdrawn from the receiver, section 18
of plug 6 which has been under compression and has been stretched and
expanded over the ribs 86 of the rod 14, begins to resile and return
toward the configuration shown in FIG. 7. This causes the space 82 to be
closed, completely or substantially, and all fluid which has been in that
space is thus forced through openings 146 into conduit 46 and on through
to conduits 42, 38, 140 and 142 and into the receiver or patient, leaving
no significant amount of fluid remaining in the valve, as will be evident
by comparison of FIGS. 9 and 10. This is the exact opposite of the
operation the prior art devices, where return of the plug to the
deactivated position has no effect on the interior volume of the cannula,
since the cannula is made of a rigid plastic or similar material and
therefore is not deformed by pressure from the plug. Thus the liquid
remaining in the interior of the cannula cannot be purged by the return of
the plug to its deactivated position. In the present invention, by
contrast, the resiling or return of the plug to its deactivated position
forces the remaining fluid in the valve downstream to the receiver or
patient.
In most cases, the return and closing action of the plug 6 (or 6') will be
adequately accomplished entirely by the resiliency of the elastic material
forming the plug, such that no outside biasing or urging of the plug is
necessary. However, if desired, one could supplement the normal resiliency
of plug 6 by, during assembly of the device, filling the space 80 with an
inert gas 144 such as nitrogen or argon, preferably under pressure. Thus,
as the device is activated and the wall of the plug 6 is forced to expand
outwardly by the rod 14 and ribs 86, it encounters the compressed gas
within the space 80 and, while reducing the volume of space 80, compresses
(or further compresses) the gas 144. Consequently, when the device is
deactivated, the compressed gas 144 acts on the outside surface of the
plug 6 and as the volume of chamber 80 begins to increase (and space 82
decrease), the pressure of the expanding gas supplements the normal
resiliency of the plug 6 material, causing the device to purge itself more
quickly and completely. The expanding compressed gas 144 forces the plug
material to assume the configuration shown in FIG. 9 more completely, with
closer fitting between the interior wall of the plug 6 and the exterior
surface of the rod 14 and ribs 86. The same effect will be seen by
comparison of FIGS. 14 and 16 for the embodiment of the rib 6' shown in
FIG. 12, involving spaces 80 and 92. (One could also achieve the same
effect by mechanical rather than pneumatic action if one were to emplace
small springs (not shown) within space 82 and in contact with the outer
surface of the plug wall and the inner surface of the housing wall, and
which would be compressed when the plug 6 expanded. Upon deactivation, the
compressed would then resile and expand, urging the plug wall inward and
assisting in decreasing the interior volume of the plug.
It will thus be seen that, unlike prior art devices in which the fluid flow
channel through the valve has a fixed volume within a cannula, the device
of the present invention with its variable volume flow path formed by the
interaction of the center rod and ribs and the expanding and contracting
interior dimension of the plug, employs a unique self-purging and pressure
generating action that causes essentially all of the fluid to be forced
into the receiver or patient. This not only keeps the valve from being
clogged by return flow of blood or other receiver fluid, but also ensures
that substantially all of the dosage of the fluid intended for the patient
or receiver is, in fact, administered, with no signficant amounts retained
or lost within the valve structure itself.
For brevity, the device and its operation have been described herein in
terms of administration of IV fluid or similar medications to a human
patient. However, it will be evident that this valve also has numerous
other uses in related medical areas, such as administration of medications
or nutrients through the gastrointestinal system of a patient. It also has
many uses outside the medical field, such as administration of small
quantities of liquid reactants or reagents in chemical or biological or
medical testing procedures, or in the precise administration and delivery
of chemical reactants in processes to produce small quantities of
specialty chemicals. Other uses may include precise delivery of standard
fluids for calibration of test instruments or for conducting hydraulic or
other fluid flow experiments or small scale production processes.
It will be evident to those skilled in the art that there are numerous
embodiments of the present invention which, while not expressly described
above, are clearly within the scope and spirit of the invention. The above
description is therefore intended to be exemplary only and the scope of
the invention is to be determined solely from the appended claims.
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